Out of curiosity (and so I can tell whether the bigger power supplies are actually necessary next time I built a machine) I would like to measure how much power my PC is currently using, e.g. during 3D games that place demand on the 3D card, etc.
I would also like a multimeter for general use (checking power supplies are still behaving, and so on).
Can a cheap clamp meter do both? I'm under the impression that a clamp meter for active appliance measurments really needs to be "True RMS" (because of distortion introduced by noisy drives). But is it possible to measure power by measuring the voltage on the power cord, then measuring current at different times? Or would the voltage change significantly as the demand changed, making current-only calculations useless?
Can a clamp meter perform the same tasks as a standard digital multimeter (assuming you have test leads with it)?
Basically, is it possible to closely (within 10% of true power requirement) measure and calculate appliance power use with only a standard (well, True RMS) clamp meter, or would the full-whack, expensive "Clamp-on Power Meter" be required to do this?
Thanks for any advice you can offer.